Jet propulsion device for airscrews or rotary wings



March 25, 1952 R. POUIT 2,590,457

' JET PROPULSION DEVICE FOR AIRSCREWS 0R ROTARY WINGS Filed April 9, 1947 2 SHEETSSHEET l wi t/V701? ROBERT POUIT er M g March 25, 1952 R. PQU|T 2,590,457

JET PROPULSION DEVICE FOR AIRSCREWS OR ROTARY wmas Filed April 9, 1947 2 SHEETSSHEET 2 F910. A F5916.

INVENTUR W AME ATT 0 RN EYS Patented Mar. 25, 1952 JET PROPULSION DEVICEFOR AIRSCREWS R ROTARY WINGS Robert Poiiit, Lyon, France, assignor to Societe' Inclustrielle Generale De Mecanique Appliquee (S. I. G. M. A.) Villeurbanne (Rhone), France, a society of France Application April9, 1947, Serial No. 740,327 In France April 20, 1946 9 Claims. 1

The present invention relates to jet propulsion devices for airscrews or' rotary wings and it is more especially, although not exclusively, concerned with propulsion devices of this kind for the rotary wings of helicopters.

The object of the invention is toprovide a device of this kind which is better adapted .to-meet the requirements of practice than those used up to this time, particularly from the points of view of simplicity, power per unitof weight and efficiency.

Preferred embodiments of my invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example" and in which:

Fig. 1 diagrammatically shows a jet propelled rotary wing made according to'my invention.

Fig. 2 shows a modification;

Fig. 3 diagrammatically shows, in-a cross-section, a wing blade made according to another embodiment of the invention;

Fig. 4 is a plan view, partly in section, of a rotary wing blade of the kind shown by Fig. 3, shown on a smaller scale; v

Figs. 5 to 7 are sectional views of constructiona'l details of a wing made according to the invention.

The rotary wingis of any suitable construction, constituted for instance by two blades I, each being provided at its tip with a bent nozzle 3 through which are expelled-gases fed from the hub and'p'roducing a reaction'effect which causes the bladeto rotate.

The plant shown by Fig. 1- shows a construction which-comprises an auto-generator including a motor'piston 2| working in a motor cylinder 22 and a compressor piston 23 working in a compressor cylinder 24, and these pistons are rigid with each other and constitute a single movable unit. The motor cylinder is provided with inlet ports 25 and exhaust ports 26 controlled by the motor piston2l, and also with a fuel injector 21, ignition taking place by compression of the-charge enclosed in the motor cylinder, which works on' the two-stroke cycle. Fuel combustion in motor cylinder 22 produces the outward stroke of the piston unit 2l-23, whereas the inward stroke is obtained, in the plant shown by Fig. 3, by means of a ily-wheel a fixed ona rotating shaft connected to said pistonunitthrough a crankb and a connecting rod 0. Of course, theauto-generator may be of thefree piston type, without crank or connecting rod, the same motor cylinder cooperating, for instance, with two opposed pistons each rigid with at least one compressor piston working in acor-responding compressor cylinder.

Compressor cylinder'24 is provided with suc- (Cl. I'm-135.4)

tion valves 28 and valves 29. The downstream side of valves 29 communicates, through a-conduit 30, with the inside of a casing 31 which surrounds motor cylinder 22 and communicates therewith when piston 21 clears ports 25.

The exhaust gases from motor cylinder 22' are evacuated through an exhaust conduit 32which leads to a gas turbine 3'3'operated by 'these'gases.

Turbine '33 is coupled with a compressor 34 including two stages 34a and 34b, with an outlet 35 between these two stages connected through a conduit 36' with the suction valve 28' of compressor cylinder 24, the amount of air that is thus diverted being adjustableby means of a valve 31. The remainder of the'air' from the first stage 34a is further compressed by the second stage 34b so as to be given, at the output of' compressor 34, a pressure'substantially equal to the pressure withwhich the gases supplied by the auto-generator leave turbine'33, after having expanded therein. The air fed by the second stage 34b of the compress'crand the gases flowing out from turbine 33 therefore cons'titute the two gas streams which, after being mixed together, serve to'feed nozzles s.

According to a modification shown by Fig.2, compressor cylinder 24 is supei'char'ged;'not with air collected between the'sta'ges 34a and 34b of compressor 34 but with air collected'at the ou-tput of the'high pressure stage 34bofsa'id coinpressor, thisoutput being connected with the inletof compressor cylinder 24 through a conduit 36a, provided with -a-control'va1ve 3"la. Of course, the compressor cylinder might be fed directly from the atmosphere.

In certain systems, I may also provide both conduits 36 and 36a for supercharging the Compressor element of the auto-generator either with air collected from an intermediate stage of compressor 34, for low altitudefi-yingof' the aerodyne, or with air collected from the high pressure stage of compressor .34, for flights at high altitude, according to therespective" positions of control valves 31 and 31a.

According to my invention the hot :ga-s'es coming from the gas turbine and the' relatively'cold compressed air from the rotary" compressor are mixed together only immediately "before reaching the reaction nozzles; The hot gases travel inide the blades through tubes which aretheinselves located inside the colder compresse'd'air stream conduits, this air thus constituting an insulating medium which protects the .blade elements against the action of the hot gases. Preferably, the tubes that contain these gases are adapted to expand freely, especially 'in'the longitudinal direction.

An example of such an arrangement is shown by Fig. 1. Pure air supplied by compressor 34 is fed through a suitable sliding joint (not shown) to a conduit 39 which surrounds a tube 40 to which the hot gases from gas turbine 33 are fed, also through a suitable sliding joint not shown, this conduit and this tube being located. inside blade I and extending in a direction parallel to its axis. As the hot gases inside tube 40 and the colder air that surrounds aid conduit are substantially at the same pressure, it is possible without any risk of detrimental leaks, to arrange this conduit in such manner that it can expand freely, in particular in the direction of its axis. For this purpose, conduit 40 is made of at least two portions 40a and 40b connected together by a sleeve 400 which engages the respective opposite ends of portions 40a and 40b. The outer end of portion 40b is fixed at M to the tip of the blade, whereby the outer end of this portion can expand inwardly, whereas the inner end of portion 40a is fixed to the hub of the rotary wing, whereby its outer end can expand freely in the outward direction. Portion 402) carries an abutment 42 which keeps sleeve 400 in position against the action of the centrifugal force. Finally, ports 43 are provided near the outer end of the portion 40b of tube 40 to enable the hot gases, which flow through tube 40 in the direction of the arrows, to mix with the air flowing through onduit 39, immediately ahead of nozzles 3.

According to another feature of the invention, a certain amount of fuel is burned in the gases intended to produce the reaction effect, prior to their leaving reaction nozzles 3, this combustion serving to increase, preferably temporarily and especially during the take-off period, the reaction thrust at the tips of the blades, and therefore to supply a supplement of power.

Advantageously, I make use of a fuel having a high velocity of combustion, such as acetylene.

Combustion of a supplementary fuel can be caused to take place in the hot gases that flow through the inner tube 40 in View of the fact that these gases contain a high percentage of uncombined oxygen due to the excess of scavenging air in the motor cylinder from which these gases come. In this case, combustion may be caused to take place either at the inner ends of the blades, by injecting through an injector atomized fuel which burns spontaneously in the hot gases, or in said blades or near their outer ends, the fuel being then preferably introduced in the form of a gas or vapor.

In all cases, the thermal insulation of the inner conduit with respect to the structural elements of the blade protects the outer surface of the latter against excessive heating.

. I may also burn, near the end of the blade, a' certain amount of gaseous or atomized fuel either in the air surrounding the inner tube 40, or in the mixture of gas and fuel that is produced at the outlet of tube 40.

I might burn both an atomized liquid fuel at the inner ends of the blades and a gaseous or atomized fuel in the blades themselves, for instance near the ends thereof.

According to another feature of the invention, in order to reduce losses of pressure in the inner conduit through which hot gases flow from hub to tip of the blade, this inner conduit is given a section such that only a small interval is left between the wall of said conduit and the outer surface of the blade. In this interval, I provide a multiplicity of adjoining tubular passages through at least some of which a portion of a relatively cold stream constituted by air under pressure is caused to flow, advantageously with a velocity ensuring a laminar flow, whereas the hot gases, coming from the engine combustion chamber and having already expanded in the gas turbine, flow through the inner conduit together with a portion of said stream of air under pressure mixed with said gases.

For instance (Fig. 3) the cross-section of this inner conduit IOI is given a shape similar to that of the outer wall of the blade, so as to leave, between the outer surface of conduit IOI and the inner surface of blade an interval I03 of small thickness in which I provide an intermediate undulated partition I04 which thus forms in this interval a multiplicity of adjoining tubular ducts each of small section. The tubular ducts I05 that have their bases along to the outer wall I02 of the blade constitute the outer ducts, whereas the ducts, designated by I05, that have their bases along the wall of conduit IOI constitute the inner ducts.

I may cause a portion of the compressed air stream to flow through both ducts I05 and I06, but preferably this portion of the air stream flows merely through the inner ducts I06.

In both cases, the volume and therefore the velocity of the air stream flowing through these ducts is chosen to maintain a laminar flow.

In the embodiment shown by Figs. 3 and 4, the relatively cold stream of air under pressure is caused to flow through the inner ducts I06 which are fed, preferably, from a chamber I01 located close to the inner end of the blade (Fig. 4 and to which air under pressure is delivered through a conduit I08.

In order to determine the amount of air entering each of ducts I05, I provide, between chamber I01 and each of these conduits, a partition provided with a calibrated orifice I09. Ducts I05 open at their outer ends into chamber I I0, located ahead of reaction nozzle III and into which the hot mixture of gas and air that has flown through the inner conduit IOI is also fed.

Concerning said inner conduit IOI, which is fed through a conduit m, it is preferably made of several longitudinal sections slidable with respect to one another to permit longitudinal expansion of the whole, as already described with reference to Fig. 1. Furthermore, preferably, free transverse expansion of the wall of said conduit IOI is permitted by relative sliding of two lips z and 7 provided on said wall over its whole length (Fig. 3).

According to another feature of the invention, the outer ducts I05 are placed in communication, on the one hand, through apertures II2, with the outer side of the wing and on the other hand with a space at a pressure either higher or lower than atmospheric pressure, so as thus to exert on the friction boundary layer on the outer side of wall I02, a blowing or a suction effect. This effect considerably reduces the drag of the wing.

The inside of ducts I05 may be connected, through calibrated tubes II3, with a common chamber IM which is itself in communication with blowing or sucking means, through a conduit I55 (as shown in solid lines in Fig. 4). Eventually suitably loaded valves may be provided on said tubes I I3.

According to another feature of the invention, the pressure conditions in ducts I05 for sucking in, through apertures II2, the boundary layer on the outer surface of wall I02, are obtained *tionssuch as H31, H82, etc. (Fig. 6).

hams-v through the-suction exerted by the gases issuing from nozzle I l I in an annular chamber H6 which surrounds said nozzle and which communicates, through calibrated orifices H1, with ducts 105 (as shown in dotted lines in Fig. 7).

f In this case, of course, tubes H3 and chamber I'M-"are not used.

In all' cases, a good heat insulation between 'theinner conduit HH and the outer wall I02 is obtained, owing to the provision of ducts I05 and lflfil'linthe interval between said conduit and said wa This heat insulation is practically unaffected by the thermal conductivity of the undulated partition H14 which serves to constitute these ducts, even if this undulated wall is metallic.

However, in order further to reduce the effect of this conductivity, this undulated partition may be made of a material which is a bad conductor of heat or a layer of an insulating material may be interposed between the wallof conduit 'Hll and the undulated partition. Although it is not necessary to ensure fluidtightness between ducts Hi6 and inner conduit l'lll since the gases flowing therethrough are substantially at the same pressure, I may, in order to improve the resistance of the structure, stifien the assembly of outer wall I02 and undulated wall M4 by securing the latter, for instance by welding, on the one hand to the outer wall and, on the other hand, to an inner metal sheetl-IB, as shown by Fig. -5. Elements Hi2 andlll l-may be assembled together by electrical "spot welding. Concerning the welding of elements H14 and I 18 together, it may be facilitated by dividing metal sheet H8 into separate sec- Each of the-edges a of the sections of this metal sheet may' bebent (edges shown in dotted lines by Fig. '6) i for making first the longitudinal welds b between partition I04 and the metal sheet sections H81, H82, etc., and finishing the assembly by welding of'the bent edges together, as shown at m in solid lines.

' Furthermore, it is advantageous to constitute the wing structure by assembly of two box-like half-shells c and d, forming respectively the upper side and the under side of the wing and these elements being assembled together for instance byexternal welding along their leading edges (see the assembly shown by Fig. 6) and their trailing edges (see the assembly shown by Fig. 7).

Finally, the profile is completed, concerning the leading edge for instance, by addition of solder e and, concerning the trailing edge, by assembly to the main body of the wing of a trail ing edge portion i, this assembly being for instance obtained in any suitable manner such as welding or riveting or preferably, as shown by Fig. 7, by means of longitudinal rods g and h engaged in hinges formed alternately in the rear edge of the main body 0-01 of the wing and in the rea'r'end portion 7.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1*. In connection with an aerodynamic rotary blade, a propulsion device for said blade which comprises, in combination, an internal combustion device, a gas turbine, means for conveying the exhaust gases of said combustion device to the input of said turbine, a rotary air compressor driven by said turbine adapted to supply an air stream at a pressure substantially equalto that of the gas stream leaving said turbine, a tube extending through said blade from hub to tip connected with the output of said turbine, a conduit surrounding said tube, the annular space between said tube and said conduit being connected with the output of said air compressor, and jet propulsion means at the tip of said blade supplied with the streams from said tube and said annular space.

2. In connection with an aerodynamic rotary blade, a propulsion device for said blade which comprises, in combination, an internal combustion device, a gas turbine, means for conveying the exhaust gases of said combustion device to the input of said turbine, a rotary air compressor driven by said turbine adapted to supply an air stream at a pressure substantially equal to that of the gas stream leaving said turbine, a tube extending through said blade from hub to tip connected with the output of said turbine, a conduit surrounding said tube, the annular space between said tube and said conduit being connected with the output of said air compres-- sor, said tube being provided, near the blade tip, with holes opening into said annular space, for mixing said gas and air streams, and a reaction nozzle at the tip of said blade mounted to be supplied with the mixture of said streams.

3. In connection with an aerodynamic rotary .blade, a propulsion device for said blade which comprises, in combination, an internal combustion device, a gas turbine, means for conveying the exhaust gases of said combustion device to the input of said turbine, a rotary air compressor driven by said turbine adapted to supply an air stream at a pressure substantially equal to that of the gas stream leaving said turbine, a tube extending through said blade from hub to tip connected with the output of said turbine, said tube being of telescopic construction to permit variable expansion under the effect of heat, a conduit surrounding said tube, the annular space between said tube and said conduit being connected with the output of said air compressor, and jet propulsion means at the tip of said blade supplied with the air and gas streams from said conduit and tube respectively.

4. A propulsion device according to claim 1 further including means for injecting fuel into said tube.

5. In a flying machine, the combination of a rotary aerofoil blade including an outer wall of aerofoilcross-section, an inner Wall at least substantially parallel to said outer wall formingan inner conduit therein, an undulated partition in the interval between said inner and outer walls having its ridges running in the hub to tip direc-'- tion of the blade alternately along said inner and.

outer walls, so as to form a multiplicity of longitudinal tubular ducts in said interval and a reaction nozzle at the tip of said blade having its inlet in communication with said inner conduit, an internal combustion engine, a gas turbine, means for conveying the exhaust gases from said engine to the input of said turbine, a rotary air compressor driven by said turbine adapted to supply an air stream at a pressure substantially equal to that of the gas stream leaving said turbine, means for circulating atleast "a portion of said air stream through those of said ducts a portion of the surface of which is constituted by said inner wall, and means for delivering said gas stream into said inner conduit near the hub of said blade.

6. In a flying machine, the combination of a rotary aerofoil blade including an outer wall of aerofoil cross-section, an inner wall at least substantially parallel to said outer wall forming an inner conduit therein, an undulated partition in the interval between said inner and outer walls having its ridges running in the hub to tip direction of the blade alternately along said inner and outer walls, so as to form a multiplicity of longitudinal tubular ducts in said interval and a reaction nozzle at the tip of said blade having its inlet in communication with said inner conduit, an internal combustion engine, a gas turbine, means for conveying the exhaust gases from said engine to the input of said turbine, a rotary air compressor driven by said turbine adapted to supply an air stream at a pressure substantially equal to that of the gas stream leaving said turbine, means for circulating a portion of said air stream through those of said ducts a portion of the surface of which is constituted by said inner wall and means for delivering said gas stream flowing out from said turbine and the remainder of the air stream delivered by said compressor both into said inner conduit near the hub of said blade.

7. In a flying machine, the combination of a rotary aerofoil blade including an outer wall of aerofoil cross-section, an inner wall at least substantially parallel to said outer wall forming an inner conduit therein, an undulated partition in the interval between said inner and outer walls having its ridges running in the hub to tip direction of the blade alternately along said inner and outer walls, so as to form a multiplicity of longitudinal tubular ducts in said interval, a reaction nozzle at the tip of said blade having its inlet in communication with said inner conduit, means forming a chamber in communication with those of said ducts a portion of the surface of which is constituted by said outer wall, said outer wall being provided with holes connecting said last mentioned ducts directly with the atmosphere, and means for keeping in said chamber a pressure different from atmospheric pressure, so as at least partly to eliminate the boundary layer on the external face of said outer wall, an internal combustion engine, a gas turbine, means for conveying the exhaust gases from said engine to the input of said turbine, a rotary air compressor driven by said turbine adapted to supply an air stream at a pressure substantially equal to that of the gas stream leaving said turbine, means for circulating at least a portion of said air stream through those of said ducts a portion of the surface of which is constituted by said inner wall, and means for deliverin said gas stream into said inner conduit near the hub of said blade.

8. In an airplane, the combination of a rotary aerofoil blade including an outer wall of aerofoil cross-section, an inner wall at least substantially parallel to said outer wall forming an inner conduit therein, an undulated partition in the interval between said inner and outer walls having its ridges running in the hub to tip direction of the blade alternately along said inner and outer Walls, so as to form a multiplicity of longitudinal tubular ducts in said interval, a reaction nozzle at the tip of said blade having its inlet in communication with said inner conduit, means forming, at the tip of said blade, 9. chamber in communication with those of said ducts a portion of the surface of which is constituted by said outer wall, said outer wall being provided with holes connecting said last mentioned ducts directly with the atmosphere, said chamber being connected with said nozzle so as to be placed, through an ejector-like action exerted by said nozzle, at a pressure lower than atmospheric pressure, an internal combustion engine, a gas turbine, means for conveying the exhaust gases from said engine to the input of said turbine, a rotary air compressor driven by said turbine adapted to supply an air stream at a pressure substantially equal to that of the gas stream leaving said turbine, means for circulating a portion of said air stream through those of said ducts a portion of the surface of which is constituted by said inner wall and means for delivering said gas stream flowing out from said turbine and the remainder of the air stream delivered by said compressor both into said inner conduit near the hub of said blade.

9. In an airplane, the combination of a rotary aerofoil blade including two box-like half-shells, one forming the upper portion and the other the lower portion of said blade, each half-shell including an outer wall, an inner wall at least substantially parallel to said outer wall and an undulated partition in the interval between said inner and outer Walls having its ridges running in the hub to tip direction of the blade alternately along said inner and outer walls respectively, means for assembling said upper and lower half-shells along the leadin and trailing edges of said aerofoil component, and a reaction nozzle at the tip of said blade having its inlet in communication with said inner conduit, an internal combustion engine, a gas turbine, means for conveying the exhaust gases from said engine to the input of said turbine, a rotary air compressor driven by said turbine adapted to supply an air stream at a pressure substantially equal to that of the gas stream leaving said turbine, means for circulating at least a portion of said air stream through those of said ducts a portion of the surface of which is constituted by said inner Wall, and means for delivering said gas stream into said inner conduit near the hub of said blade.

ROBERT POUIT.

REFERENCES CITED The following references are of record in the file of this patent:

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